Developing as an imposing puck moving and mobile defenseman, Krupp steadily improved his point totals each year with the Sabres and in the 1990–91 season was selected to the participate in the NHL All-Star game, becoming just the second German named behind Walt Tkaczuk. At the beginning of the 1991–92 season, Krupp was included by the Sabres in the Blockbuster trade that sent Pierre Turgeon to the New York Islanders for Pat LaFontaine on October 25, 1991.[2] Krupp quickly settled with the Islanders, finishing second behind Tom Kurvers in defenseman scoring with 35 points in 59 games.

After announcing his retirement Krupp coached the TPHThunder AAA Bantam hockey team. This was short lived as he was quickly appointed as an Assistant Coach to the German Junior National team. Working up the ranks, he was appointed as an Assistant Coach to the Men's National team under Greg Poss in 2005. Then, shortly before the Torino Olympics, Krupp was made coach of the German national ice hockey team on December 15, 2005, replacing Poss who resigned under heavy fire from the German media. Krupp had strong feelings that the German media never gave Poss his fair chance, using the excuse that Poss was from North America to stonewall any chance Poss may have had of success.

However, Krupp had drastic lineup changes in store before the 2005 World Championship "B-Pool" tournament. Facing strong criticism from the German tabloid media, Krupp chose a team of young players, leaving behind seven veterans from the Torino team, in addition to the top goal scorer in the German league. Skewing the team towards youth, he chose players who had led the Junior National team out of the "B-Pool" to lead the Germans past Israel, Hungary, Great Britain, Japan and the home country France. With an unheard of average age of 22, the Germans outscored opponents 35–4 during their four game ascent into the "A" group.

Krupp maintains his Atlanta area home, and volunteers coaching with his son's youth team. Using his North America base, Krupp has brought several young German players to North America for a variety of tournaments and camps, in addition to opening his home to two Hurricane Katrina refugees who played on his son's youth team. Married to an American dog sled racer, Valerie Buck-Krupp, he likens himself to German soccer coach, Jürgen Klinsmann, who also resides in the US, married to an American, and schooling his children in an International School. Upon his retirement, Krupp was immediately inducted into the German Hockey Hall of Fame, as a player. In mid 2009, Krupp returned to Germany to reside in preparation for hosting the 2010 World Championships.[5]